The deal will see the company purchase roughly 675,000MWh of renewable energy annually from the Pilot Hill Wind Project, equivalent to the power needs of 70,000 homes in Illinois.

Robert Bernard, Microsoft's chief environmental strategist said, "By purchasing wind, we will reduce the overall amount of emissions associated with operating Microsoft facilities and hopefully spur additional investment in renewable energy. Because the Chicago datacenter draws power from the Illinois power grid, projects like Pilot Hill help provide a non-polluting source of energy that displaces greenhouse gas emissions from conventional power."

The project has already entered the construction phase and should be delivering energy in 2015.

In his blog post, Bernard added, "The Pilot Hill Wind Project is another major step to continue our drive to reduce our environmental footprint and to be carbon neutral."

David Pomerantz, the senior energy campaigner at Greenpeace, has also welcomed the news.

"Microsoft's wind energy purchase shows that it intends to compete in the race among cloud computing companies to power their operations with renewable energy," he said.

The project emerges hot on the heels of Apple's own announcement that it will be investing $55 million into a 100 acre solar farm in North Carolina to fuel its iCloud services. Amazon CEO Jeff Bezos has been criticised by Greenpeace, however, for not encouraging the firm to support its own renewable energy projects.